From: Jiang Liu <liuj97@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Jiang Liu <jiang.liu@huawei.com>,
Wen Congyang <wency@cn.fujitsu.com>, Mel Gorman <mgorman@suse.de>,
Minchan Kim <minchan@kernel.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Michal Hocko <mhocko@suse.cz>, Jianguo Wu <wujianguo@huawei.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2, part3 01/12] mm: enhance free_reserved_area() to support poisoning memory with zero
Date: Sun, 17 Mar 2013 01:48:14 +0800 [thread overview]
Message-ID: <5144B05E.9040307@gmail.com> (raw)
In-Reply-To: <CAMuHMdUbg67zLqn7x_vpzEWpbuwjmxO5MYRNJQhxMpqtLxTVOg@mail.gmail.com>
On 03/17/2013 01:37 AM, Geert Uytterhoeven wrote:
> On Sat, Mar 16, 2013 at 6:03 PM, Jiang Liu <liuj97@gmail.com> wrote:
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -5130,13 +5130,13 @@ unsigned long free_reserved_area(unsigned long start, unsigned long end,
>> pos = start = PAGE_ALIGN(start);
>> end &= PAGE_MASK;
>> for (pages = 0; pos < end; pos += PAGE_SIZE, pages++) {
>> - if (poison)
>> + if ((unsigned int)poison <= 0xFF)
>
> "if (poison >= 0)"? No cast needed.
Hi Geert,
We constraints valid inputs as [0, UCHAR_MAX], so the code follows the comment as below.
/*
* Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
* into the buddy system. The freed pages will be poisoned with pattern
* "poison" if it's within range [0, UCHAR_MAX].
* Return pages freed into the buddy system.
*/
Regards!
Gerry
>
>> memset((void *)pos, poison, PAGE_SIZE);
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
>
--
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WARNING: multiple messages have this Message-ID (diff)
From: Jiang Liu <liuj97@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Jiang Liu <jiang.liu@huawei.com>,
Wen Congyang <wency@cn.fujitsu.com>, Mel Gorman <mgorman@suse.de>,
Minchan Kim <minchan@kernel.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Michal Hocko <mhocko@suse.cz>, Jianguo Wu <wujianguo@huawei.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2, part3 01/12] mm: enhance free_reserved_area() to support poisoning memory with zero
Date: Sun, 17 Mar 2013 01:48:14 +0800 [thread overview]
Message-ID: <5144B05E.9040307@gmail.com> (raw)
In-Reply-To: <CAMuHMdUbg67zLqn7x_vpzEWpbuwjmxO5MYRNJQhxMpqtLxTVOg@mail.gmail.com>
On 03/17/2013 01:37 AM, Geert Uytterhoeven wrote:
> On Sat, Mar 16, 2013 at 6:03 PM, Jiang Liu <liuj97@gmail.com> wrote:
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -5130,13 +5130,13 @@ unsigned long free_reserved_area(unsigned long start, unsigned long end,
>> pos = start = PAGE_ALIGN(start);
>> end &= PAGE_MASK;
>> for (pages = 0; pos < end; pos += PAGE_SIZE, pages++) {
>> - if (poison)
>> + if ((unsigned int)poison <= 0xFF)
>
> "if (poison >= 0)"? No cast needed.
Hi Geert,
We constraints valid inputs as [0, UCHAR_MAX], so the code follows the comment as below.
/*
* Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
* into the buddy system. The freed pages will be poisoned with pattern
* "poison" if it's within range [0, UCHAR_MAX].
* Return pages freed into the buddy system.
*/
Regards!
Gerry
>
>> memset((void *)pos, poison, PAGE_SIZE);
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
>
next prev parent reply other threads:[~2013-03-16 17:48 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-16 17:03 [PATCH v2, part3 00/12] accurately calculate zone->managed_pages Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 01/12] mm: enhance free_reserved_area() to support poisoning memory with zero Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:37 ` Geert Uytterhoeven
2013-03-16 17:37 ` Geert Uytterhoeven
2013-03-16 17:48 ` Jiang Liu [this message]
2013-03-16 17:48 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 02/12] mm/ARM64: kill poison_init_mem() Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-17 21:46 ` Will Deacon
2013-03-17 21:46 ` Will Deacon
2013-03-17 21:46 ` Will Deacon
2013-03-18 17:21 ` Jiang Liu
2013-03-18 17:21 ` Jiang Liu
2013-03-18 17:21 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 03/12] mm/x86: use common help functions to furthur simplify code Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 04/12] mm/tile: use common help functions to free reserved pages Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 05/12] mm/powertv: " Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 06/12] mm/acornfb: " Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 07/12] mm: accurately calculate zone->managed_pages for highmem zones Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 08/12] mm: use a dedicated lock to protect totalram_pages and zone->managed_pages Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 09/12] mm: avoid using __free_pages_bootmem() at runtime Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 10/12] mm: correctly update zone->mamaged_pages Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 11/12] mm: report available pages as "MemTotal" for each NUMA node Jiang Liu
2013-03-16 17:03 ` Jiang Liu
2013-03-16 17:03 ` [PATCH v2, part3 12/12] mm: concentrate adjusting of totalram_pages Jiang Liu
2013-03-16 17:03 ` Jiang Liu
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